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Thursday, January 16, 2020

Semiconductor device fabrication

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Semiconductor_device_fabrication
 
NASA's Glenn Research Center clean room
 
Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically the metal-oxide-semiconductor (MOS) devices used in the integrated circuit (IC) chips that are present in everyday electrical and electronic devices. It is a multiple-step sequence of photolithographic and chemical processing steps (such as surface passivation, thermal oxidation, planar diffusion and junction isolation) during which electronic circuits are gradually created on a wafer made of pure semiconducting material. Silicon is almost always used, but various compound semiconductors are used for specialized applications.

The entire manufacturing process, from start to packaged chips ready for shipment, takes six to eight weeks and is performed in highly specialized facilities referred to as foundries or fabs. In more advanced semiconductor devices, such as modern 14/10/7 nm nodes, fabrication can take up to 15 weeks (about 4 months) with 11–13 weeks (3 to 4 months) being the industry average. Production in advanced fabrication facilities is completely automated, and carried out in a hermetically sealed, nitrogen environment to improve yield (the proportion of microchips in a wafer that function correctly) with FOUPs and automated material handling systems taking care of the transport of wafers from machine to machine. All machinery as well as FOUPs contain an internal nitrogen atmosphere. The air inside the machinery and the FOUPs is usually kept cleaner than the surrounding air in the cleanroom. This internal atmosphere is known as a mini environment. Fab's need for large amounts of liquid nitrogen arises from the need to mantain the nitrogen atmosphere inside produciton machnery and FOUPs, which are constantly purged with nitrogen.

By industry standard, each generation of the semiconductor manufacturing process, also known as technology node, is designated by the process’s minimum feature size. Technology nodes, also known as "process technologies" or simply "nodes", are typically indicated by the size in nanometers (or historically micrometers) of the process's transistor gate length.

History


20th century

The first MOSFET (metal-oxide-silicon field-effect transistor) semiconductor devices were fabricated by Egyptian engineer Mohamed M. Atalla and Korean engineer Dawon Kahng at Bell Labs between 1959 and 1960. There were originally two types of MOSFET technology, PMOS (p-type MOS) and NMOS (n-type MOS). Both types were developed by Atalla and Kahng when they originally invented the MOSFET, fabricating both PMOS and NMOS devices at 20 µm and 10 µm scales.

An improved type of MOSFET technology, CMOS, was developed by Chih-Tang Sah and Frank Wanlass at Fairchild Semiconductor in 1963. CMOS was commercialised by RCA in the late 1960s. RCA commercially used CMOS for its 4000-series integrated circuits in 1968, starting with a 20 µm process before gradually scaling to a 10 µm process over the next several years.

Semiconductor device manufacturing has since spread from Texas and California in the 1960s to the rest of the world, including Asia, Europe, and the Middle East. 

21st century

The semiconductor industry is a global business today. The leading semiconductor manufacturers typically have facilities all over the world. Samsung Electronics, the world's largest manufacturer of semiconductors, has facilities in South Korea and the US. Intel, the second largest manufacturer, has facilities in Europe and Asia as well as the US. TSMC, the world's largest pure play foundry, has facilities in Taiwan, China, Singapore, and the US. Qualcomm and Broadcom are among the biggest fabless semiconductor companies, outsourcing their production to companies like TSMC. They also have facilities spread in different countries. 

Since 2009, "node" has become a commercial name for marketing purposes that indicates new generations of process technologies, without any relation to gate length, metal pitch or gate pitch. For example, GlobalFoundries' 7 nm process is similar to Intel's 10 nm process, thus the conventional notion of a process node has become blurred. Additionally, TSMC and Samsung's 10 nm processes are only slightly denser than Intel's 14 nm in transistor density. They are actually much closer to Intel's 14 nm process than they are to Intel's 10 nm process (e.g. Samsung's 10 nm processes' fin pitch is the exact same as that of Intel's 14 nm process: 42 nm).

As of 2019, 14 nanometer and 10 nanometer chips are in mass production by Intel, UMC, TSMC, Samsung, Micron, SK Hynix, Toshiba Memory and GlobalFoundries, with 7 nanometer process chips in mass production by TSMC and Samsung, although their 7 nanometer node definition is similar to Intel's 10 nanometer process. The 5 nanometer process began being produced by Samsung in 2018. As of 2019, the node with the highest transistor density is TSMC's 5 nanometer N5 node, with a density of 171.3 million transistors per square millimeter. In 2019, Samsung and TSMC announced plans to produce 3 nanometer nodes. GlobalFoundries has decided to stop the development of new nodes beyond 12 nanometers in order to save resources, as it has determined that setting up a new fab to handle sub-12nm orders would be beyond the company's financial abilities. As of 2019, Samsung is the industry leader in advanced semiconductor scaling, followed by TSMC and then Intel.

List of steps

This is a list of processing techniques that are employed numerous times throughout the construction of a modern electronic device; this list does not necessarily imply a specific order. Equipment for carrying out these processes is made by a handful of companies. All equipment needs to be tested before a semiconductor fabrication plant is started. 
Progress of miniaturisation, and comparison of sizes of semiconductor manufacturing process nodes with some microscopic objects and visible light wavelengths.

Prevention of contamination and defects

When feature widths were far greater than about 10 micrometres, semiconductor purity was not as big of an issue as it is today in device manufacturing. As devices became more integrated, cleanrooms must become even cleaner. Today, fabrication plants are pressurized with filtered air to remove even the smallest particles, which could come to rest on the wafers and contribute to defects. The workers in a semiconductor fabrication facility are required to wear cleanroom suits to protect the devices from human contamination. To prevent oxidation and to increase yield, FOUPs and semiconductor capital equipment may have a pure nitrogen environment with ISO class 1 levels of dust. 

Wafers

A typical wafer is made out of extremely pure silicon that is grown into mono-crystalline cylindrical ingots (boules) up to 300 mm (slightly less than 12 inches) in diameter using the Czochralski process. These ingots are then sliced into wafers about 0.75 mm thick and polished to obtain a very regular and flat surface. 

Processing

In semiconductor device fabrication, the various processing steps fall into four general categories: deposition, removal, patterning, and modification of electrical properties.
Modern chips have up to eleven metal levels produced in over 300 sequenced processing steps.

Front-end-of-line (FEOL) processing

FEOL processing refers to the formation of the transistors directly in the silicon. The raw wafer is engineered by the growth of an ultrapure, virtually defect-free silicon layer through epitaxy. In the most advanced logic devices, prior to the silicon epitaxy step, tricks are performed to improve the performance of the transistors to be built. One method involves introducing a straining step wherein a silicon variant such as silicon-germanium (SiGe) is deposited. Once the epitaxial silicon is deposited, the crystal lattice becomes stretched somewhat, resulting in improved electronic mobility. Another method, called silicon on insulator technology involves the insertion of an insulating layer between the raw silicon wafer and the thin layer of subsequent silicon epitaxy. This method results in the creation of transistors with reduced parasitic effects. 

Gate oxide and implants

Front-end surface engineering is followed by growth of the gate dielectric (traditionally silicon dioxide), patterning of the gate, patterning of the source and drain regions, and subsequent implantation or diffusion of dopants to obtain the desired complementary electrical properties. In dynamic random-access memory (DRAM) devices, storage capacitors are also fabricated at this time, typically stacked above the access transistor (the now defunct DRAM manufacturer Qimonda implemented these capacitors with trenches etched deep into the silicon surface).

Back-end-of-line (BEOL) processing


Metal layers

Once the various semiconductor devices have been created, they must be interconnected to form the desired electrical circuits. This occurs in a series of wafer processing steps collectively referred to as BEOL (not to be confused with back end of chip fabrication, which refers to the packaging and testing stages). BEOL processing involves creating metal interconnecting wires that are isolated by dielectric layers. The insulating material has traditionally been a form of SiO2 or a silicate glass, but recently new low dielectric constant materials are being used (such as silicon oxycarbide), typically providing dielectric constants around 2.7 (compared to 3.82 for SiO2), although materials with constants as low as 2.2 are being offered to chipmakers.

Interconnect

Synthetic detail of a standard cell through four layers of planarized copper interconnect, down to the polysilicon (pink), wells (greyish) and substrate (green).
 
Historically, the metal wires have been composed of aluminum. In this approach to wiring (often called subtractive aluminum), blanket films of aluminum are deposited first, patterned, and then etched, leaving isolated wires. Dielectric material is then deposited over the exposed wires. The various metal layers are interconnected by etching holes (called "vias") in the insulating material and then depositing tungsten in them with a CVD technique; this approach is still used in the fabrication of many memory chips such as dynamic random-access memory (DRAM), because the number of interconnect levels is small (currently no more than four). 

More recently, as the number of interconnect levels for logic has substantially increased due to the large number of transistors that are now interconnected in a modern microprocessor, the timing delay in the wiring has become so significant as to prompt a change in wiring material (from aluminum to copper interconnect layer) and a change in dielectric material (from silicon dioxides to newer low-K insulators). This performance enhancement also comes at a reduced cost via damascene processing, which eliminates processing steps. As the number of interconnect levels increases, planarization of the previous layers is required to ensure a flat surface prior to subsequent lithography. Without it, the levels would become increasingly crooked, extending outside the depth of focus of available lithography, and thus interfering with the ability to pattern. CMP (chemical-mechanical planarization) is the primary processing method to achieve such planarization, although dry etch back is still sometimes employed when the number of interconnect levels is no more than three.

Wafer test

The highly serialized nature of wafer processing has increased the demand for metrology in between the various processing steps. For example, thin film metrology based on ellipsometry or reflectometry is used to tightly control the thickness of gate oxide, as well as the thickness, refractive index and extinction coefficient of photoresist and other coatings. Wafer test metrology equipment is used to verify that the wafers haven't been damaged by previous processing steps up until testing; if too many dies on one wafer have failed, the entire wafer is scrapped to avoid the costs of further processing. Virtual metrology has been used to predict wafer properties based on statistical methods without performing the physical measurement itself.

Device test

Once the front-end process has been completed, the semiconductor devices are subjected to a variety of electrical tests to determine if they function properly. The proportion of devices on the wafer found to perform properly is referred to as the yield. Manufacturers are typically secretive about their yields, but it can be as low as 30%. Process variation is one among many reasons for low yield.

The fab tests the chips on the wafer with an electronic tester that presses tiny probes against the chip. The machine marks each bad chip with a drop of dye. Currently, electronic dye marking is possible if wafer test data is logged into a central computer database and chips are "binned" (i.e. sorted into virtual bins) according to the predetermined test limits. The resulting binning data can be graphed, or logged, on a wafer map to trace manufacturing defects and mark bad chips. This map can also be used during wafer assembly and packaging.

Chips are also tested again after packaging, as the bond wires may be missing, or analog performance may be altered by the package. This is referred to as the "final test". 

Usually, the fab charges for testing time, with prices in the order of cents per second. Testing times vary from a few milliseconds to a couple of seconds, and the test software is optimized for reduced testing time. Multiple chip (multi-site) testing is also possible, because many testers have the resources to perform most or all of the tests in parallel.

Chips are often designed with "testability features" such as scan chains or a "built-in self-test" to speed testing, and reduce testing costs. In certain designs that use specialized analog fab processes, wafers are also laser-trimmed during testing, in order to achieve tightly-distributed resistance values as specified by the design.

Good designs try to test and statistically manage corners (extremes of silicon behavior caused by a high operating temperature combined with the extremes of fab processing steps). Most designs cope with at least 64 corners. 

Die preparation

Once tested, a wafer is typically reduced in thickness in a process also known as "backlap", "backfinish" or "wafer thinning" before the wafer is scored and then broken into individual dice, a process known as wafer dicing. Only the good, unmarked chips are packaged. 

Packaging

Plastic or ceramic packaging involves mounting the die, connecting the die pads to the pins on the package, and sealing the die. Tiny bondwires are used to connect the pads to the pins. Originally, wires were attached by hand, but now specialized machines perform the task. Traditionally, these wires have been composed of gold, leading to a lead frame (pronounced "leed frame") of solder-plated copper; lead is poisonous, so lead-free "lead frames" are now mandated by RoHS.

Chip scale package (CSP) is another packaging technology. A plastic dual in-line package, like most packages, is many times larger than the actual die hidden inside, whereas CSP chips are nearly the size of the die; a CSP can be constructed for each die before the wafer is diced.

The packaged chips are retested to ensure that they were not damaged during packaging and that the die-to-pin interconnect operation was performed correctly. A laser then etches the chip's name and numbers on the package. 

Hazardous materials

Many toxic materials are used in the fabrication process. These include:
It is vital that workers should not be directly exposed to these dangerous substances. The high degree of automation common in the IC fabrication industry helps to reduce the risks of exposure. Most fabrication facilities employ exhaust management systems, such as wet scrubbers, combustors, heated absorber cartridges, etc., to control the risk to workers and to the environment. 


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Green computing (updated)

From Wikipedia, the free encyclopedia
 
Green computing, green ICT as per International Federation of Global & Green ICT "IFGICT", green IT, or ICT sustainability, is the study and practice of environmentally sustainable computing or IT.
 
The goals of green computing are similar to green chemistry: reduce the use of hazardous materials, maximize energy efficiency during the product's lifetime, the recyclability or biodegradability of defunct products and factory waste. Green computing is important for all classes of systems, ranging from handheld systems to large-scale data centers.

Many corporate IT departments have green computing initiatives to reduce the environmental effect of their IT operations.

Origins

Energy Star logo
 
In 1992, the U.S. Environmental Protection Agency launched Energy Star, a voluntary labeling program that is designed to promote and recognize the energy efficiency in monitors, climate control equipment, and other technologies. This resulted in the widespread adoption of sleep mode among consumer electronics. Concurrently, the Swedish organization TCO Development launched the TCO Certification program to promote low magnetic and electrical emissions from CRT-based computer displays; this program was later expanded to include criteria on energy consumption, ergonomics, and the use of hazardous materials in construction.

Regulations and industry initiatives

The Organisation for Economic Co-operation and Development (OECD) has published a survey of over 90 government and industry initiatives on "Green ICTs", i.e. information and communication technologies, the environment and climate change. The report concludes that initiatives tend to concentrate on the greening ICTs themselves rather than on their actual implementation to tackle global warming and environmental degradation. In general, only 20% of initiatives have measurable targets, with government programs tending to include targets more frequently than business associations.

Government

Many governmental agencies have continued to implement standards and regulations that encourage green computing. The Energy Star program was revised in October 2006 to include stricter efficiency requirements for computer equipment, along with a tiered ranking system for approved products.

By 2008, 26 US states established statewide recycling programs for obsolete computers and consumer electronics equipment. The statutes either impose an "advance recovery fee" for each unit sold at retail or require the manufacturers to reclaim the equipment at disposal.

In 2010, the American Recovery and Reinvestment Act (ARRA) was signed into legislation by President Obama. The bill allocated over $90 billion to be invested in green initiatives (renewable energy, smart grids, energy efficiency, etc.) In January 2010, the U.S. Energy Department granted $47 million of the ARRA money towards projects that aim to improve the energy efficiency of data centers. The projects provided research to optimize data center hardware and software, improve power supply chain, and data center cooling technologies.

Industry

  • Climate Savers Computing Initiative (CSCI) is an effort to reduce the electric power consumption of PCs in active and inactive states. The CSCI provides a catalog of green products from its member organizations, and information for reducing PC power consumption. It was started on 2007-06-12. The name stems from the World Wildlife Fund's Climate Savers program, which was launched in 1999. The WWF is also a member of the Computing Initiative.
  • The Green Electronics Council offers the Electronic Product Environmental Assessment Tool (EPEAT) to assist in the purchase of "greener" computing systems. The Council evaluates computing equipment on 51 criteria - 23 required and 28 optional - that measure a product's efficiency and sustainability attributes. Products are rated Gold, Silver, or Bronze, depending on how many optional criteria they meet. On 2007-01-24, President George W. Bush issued Executive Order 13423, which requires all United States Federal agencies to use EPEAT when purchasing computer systems.
  • The Green Grid is a global consortium dedicated to advancing energy efficiency in data centers and business computing ecosystems. It was founded in February 2007 by several key companies in the industry – AMD, APC, Dell, HP, IBM, Intel, Microsoft, Rackable Systems, SprayCool (purchased in 2010 by Parker), Sun Microsystems and VMware. The Green Grid has since grown to hundreds of members, including end-users and government organizations, all focused on improving data center infrastructure efficiency (DCIE).
  • The Green500 list rates supercomputers by energy efficiency (megaflops/watt), encouraging a focus on efficiency rather than absolute performance.
  • Green Comm Challenge is an organization that promotes the development of energy conservation technology and practices in the field of Information and Communications Technology (ICT).
  • The Transaction Processing Performance Council (TPC) Energy specification augments existing TPC benchmarks by allowing optional publications of energy metrics alongside performance results.
  • SPECpower is the first industry standard benchmark that measures power consumption in relation to performance for server-class computers. Other benchmarks which measure energy efficiency include SPECweb, SPECvirt, and VMmark.

Approaches

Modern IT systems rely upon a complicated mix of people, networks, and hardware; as such, a green computing initiative must cover all of these areas as well. A solution may also need to address end user satisfaction, management restructuring, regulatory compliance, and return on investment (ROI). There are also considerable fiscal motivations for companies to take control of their own power consumption; "of the power management tools available, one of the most powerful may still be simple, plain, common sense."

Product longevity

Gartner maintains that the PC manufacturing process accounts for 70% of the natural resources used in the life cycle of a PC. More recently, Fujitsu released a Life Cycle Assessment (LCA) of a desktop that show that manufacturing and end of life accounts for the majority of this desktop's ecological footprint. Therefore, the biggest contribution to green computing usually is to prolong the equipment's lifetime. Another report from Gartner recommends to "Look for product longevity, including upgradability and modularity." For instance, manufacturing a new PC makes a far bigger ecological footprint than manufacturing a new RAM module to upgrade an existing one.

Data center design

Data center facilities are heavy consumers of energy, accounting for between 1.1% and 1.5% of the world's total energy use in 2010 [1]. The U.S. Department of Energy estimates that data center facilities consume up to 100 to 200 times more energy than standard office buildings.

Energy efficient data center design should address all of the energy use aspects included in a data center: from the IT equipment to the HVAC(Heating, ventilation and air conditioning) equipment to the actual location, configuration and construction of the building.

The U.S. Department of Energy specifies five primary areas on which to focus energy efficient data center design best practices:
  • Information technology (IT) systems
  • Environmental conditions
  • Air management
  • Cooling systems
  • Electrical systems
Additional energy efficient design opportunities specified by the U.S. Department of Energy include on-site electrical generation and recycling of waste heat.

Energy efficient data center design should help to better utilize a data center's space, and increase performance and efficiency.

In 2018, three new US Patents make use of facilities design to simultaneously cool and produce electrical power by use of internal and external waste heat. The three patents use silo design for stimulating use internal waste heat, while the recirculation of the air cooling the silo's computing racks. US Patent 9,510,486, uses the recirculating air for power generation, while sister patent, US Patent 9,907,213, forces the recirculation of the same air, and sister patent, US Patent 10,020,436, uses thermal differences in temperature resulting in negative power usage effectiveness. Negative power usage effectiveness, makes use of extreme differences between temperatures at times running the computing facilities, that they would run only from external sources other than the power use for computing. 

Software and deployment optimization


Algorithmic efficiency

The efficiency of algorithms affects the amount of computer resources required for any given computing function and there are many efficiency trade-offs in writing programs. Algorithm changes, such as switching from a slow (e.g. linear) search algorithm to a fast (e.g. hashed or indexed) search algorithm can reduce resource usage for a given task from substantial to close to zero. In 2009, a study by a physicist at Harvard estimated that the average Google search released 7 grams of carbon dioxide (CO₂). However, Google disputed this figure, arguing instead that a typical search produced only 0.2 grams of CO₂.

Resource allocation

Algorithms can also be used to route data to data centers where electricity is less expensive. Researchers from MIT, Carnegie Mellon University, and Akamai have tested an energy allocation algorithm that successfully routes traffic to the location with the cheapest energy costs. The researchers project up to a 40 percent savings on energy costs if their proposed algorithm were to be deployed. However, this approach does not actually reduce the amount of energy being used; it reduces only the cost to the company using it. Nonetheless, a similar strategy could be used to direct traffic to rely on energy that is produced in a more environmentally friendly or efficient way. A similar approach has also been used to cut energy usage by routing traffic away from data centers experiencing warm weather; this allows computers to be shut down to avoid using air conditioning.

Larger server centers are sometimes located where energy and land are inexpensive and readily available. Local availability of renewable energy, climate that allows outside air to be used for cooling, or locating them where the heat they produce may be used for other purposes could be factors in green siting decisions.

Approaches to actually reduce the energy consumption of network devices by proper network/device management techniques are surveyed in. The authors grouped the approaches into 4 main strategies, namely (i) Adaptive Link Rate (ALR), (ii) Interface Proxying, (iii) Energy Aware Infrastructure, and (iv) Max Energy Aware Applications. 

Virtualizing

Computer virtualization refers to the abstraction of computer resources, such as the process of running two or more logical computer systems on one set of physical hardware. The concept originated with the IBM mainframe operating systems of the 1960s, but was commercialized for x86-compatible computers only in the 1990s. With virtualization, a system administrator could combine several physical systems into virtual machines on one single, powerful system, thereby conserving resources by removing need for the original hardware and reducing power and cooling consumption. Virtualization can assist in distributing work so that servers are either busy or put in a low-power sleep state. Several commercial companies and open-source projects now offer software packages to enable a transition to virtual computing. Intel Corporation and AMD have also built proprietary virtualization enhancements to the x86 instruction set into each of their CPU product lines, in order to facilitate virtual computing.

New virtual technologies, such as operating-system-level virtualization can also be used to reduce energy consumption. These technologies make a more efficient use of resources, thus reducing energy consumption by design. Also, the consolidation of virtualized technologies is more efficient than the one done in virtual machines, so more services can be deployed in the same physical machine, reducing the amount of hardware needed.

Terminal servers

Terminal servers have also been used in green computing. When using the system, users at a terminal connect to a central server; all of the actual computing is done on the server, but the end user experiences the operating system on the terminal. These can be combined with thin clients, which use up to 1/8 the amount of energy of a normal workstation, resulting in a decrease of energy costs and consumption. There has been an increase in using terminal services with thin clients to create virtual labs. Examples of terminal server software include Terminal Services for Windows and the Linux Terminal Server Project (LTSP) for the Linux operating system. Software-based remote desktop clients such as Windows Remote Desktop and RealVNC can provide similar thin-client functions when run on low power, commodity hardware that connects to a server.

Power management

The Advanced Configuration and Power Interface (ACPI), an open industry standard, allows an operating system to directly control the power-saving aspects of its underlying hardware. This allows a system to automatically turn off components such as monitors and hard drives after set periods of inactivity. In addition, a system may hibernate, when most components (including the CPU and the system RAM) are turned off. ACPI is a successor to an earlier Intel-Microsoft standard called Advanced Power Management, which allows a computer's BIOS to control power management functions.

Some programs allow the user to manually adjust the voltages supplied to the CPU, which reduces both the amount of heat produced and electricity consumed. This process is called undervolting. Some CPUs can automatically undervolt the processor, depending on the workload; this technology is called "SpeedStep" on Intel processors, "PowerNow!"/"Cool'n'Quiet" on AMD chips, LongHaul on VIA CPUs, and LongRun with Transmeta processors. 

Data center power

Data centers, which have been criticized for their extraordinarily high energy demand, are a primary focus for proponents of green computing. According to a Greenpeace study, data centers represent 21% of the electricity consumed by the IT sector, which is about 382 billion kWh a year.

Data centers can potentially improve their energy and space efficiency through techniques such as storage consolidation and virtualization. Many organizations are aiming to eliminate underutilized servers, which results in lower energy usage. The U.S. federal government has set a minimum 10% reduction target for data center energy usage by 2011. With the aid of a self-styled ultraefficient evaporative cooling technology, Google Inc. has been able to reduce its energy consumption to 50% of that of the industry average.

Operating system support

Microsoft Windows, has included limited PC power management features since Windows 95. These initially provided for stand-by (suspend-to-RAM) and a monitor low power state. Further iterations of Windows added hibernate (suspend-to-disk) and support for the ACPI standard. Windows 2000 was the first NT-based operating system to include power management. This required major changes to the underlying operating system architecture and a new hardware driver model. Windows 2000 also introduced Group Policy, a technology that allowed administrators to centrally configure most Windows features. However, power management was not one of those features. This is probably because the power management settings design relied upon a connected set of per-user and per-machine binary registry values, effectively leaving it up to each user to configure their own power management settings.

This approach, which is not compatible with Windows Group Policy, was repeated in Windows XP. The reasons for this design decision by Microsoft are not known, and it has resulted in heavy criticism. Microsoft significantly improved this in Windows Vista by redesigning the power management system to allow basic configuration by Group Policy. The support offered is limited to a single per-computer policy. The most recent release, Windows 7 retains these limitations but does include refinements for timer coalescing, processor power management, and display panel brightness. The most significant change in Windows 7 is in the user experience. The prominence of the default High Performance power plan has been reduced with the aim of encouraging users to save power.

There is a significant market in third-party PC power management software offering features beyond those present in the Windows operating system. available. Most products offer Active Directory integration and per-user/per-machine settings with the more advanced offering multiple power plans, scheduled power plans, anti-insomnia features and enterprise power usage reporting. Notable vendors include 1E NightWatchman, Data Synergy PowerMAN (Software), Faronics Power Save, Verdiem SURVEYOR and EnviProt Auto Shutdown Manager

Linux systems started to provide laptop-optimized power-management in 2005, with power-management options being mainstream since 2009.

Power supply

Desktop computer power supplies are in general 70–75% efficient, dissipating the remaining energy as heat. A certification program called 80 Plus certifies PSUs that are at least 80% efficient; typically these models are drop-in replacements for older, less efficient PSUs of the same form factor. As of July 20, 2007, all new Energy Star 4.0-certified desktop PSUs must be at least 80% efficient.

Storage

Smaller form factor (e.g., 2.5 inch) hard disk drives often consume less power per gigabyte than physically larger drives. Unlike hard disk drives, solid-state drives store data in flash memory or DRAM. With no moving parts, power consumption may be reduced somewhat for low-capacity flash-based devices.

In a recent case study, Fusion-io, manufacturer of solid state storage devices, managed to reduce the energy use and operating costs of MySpace data centers by 80% while increasing performance speeds beyond that which had been attainable via multiple hard disk drives in Raid 0. In response, MySpace was able to retire several of their servers.

As hard drive prices have fallen, storage farms have tended to increase in capacity to make more data available online. This includes archival and backup data that would formerly have been saved on tape or other offline storage. The increase in online storage has increased power consumption. Reducing the power consumed by large storage arrays, while still providing the benefits of online storage, is a subject of ongoing research.

Video card

A fast GPU may be the largest power consumer in a computer.

Energy-efficient display options include:
  • No video card - use a shared terminal, shared thin client, or desktop sharing software if display required.
  • Use motherboard video output - typically low 3D performance and low power.
  • Select a GPU based on low idle power, average wattage, or performance per watt.

Display

Unlike other display technologies, electronic paper does not use any power while displaying an image. CRT monitors typically use more power than LCD monitors. They also contain significant amounts of lead. LCD monitors typically use a cold-cathode fluorescent bulb to provide light for the display. Some newer displays use an array of light-emitting diodes (LEDs) in place of the fluorescent bulb, which reduces the amount of electricity used by the display. Fluorescent back-lights also contain mercury, whereas LED back-lights do not. 

Light on dark color schemes, also called dark mode, is a color scheme that requires less energy to display on new display technologies, such as OLED. This positively impacts battery life and energy consumption. 

While an OLED will consume around 40% of the power of an LCD displaying an image that is primarily black, it can use more than three times as much power to display an image with a white background, such as a document or web site.

 This can lead to reduced battery life and energy usage, unless a light-on-dark color scheme is used.
A recent article by Popular Science suggests that "Dark mode is easier on the eyes and battery" and displaying white on full brightness uses roughly six times as much power as pure black on a Google Pixel, which has an OLED display.  In 2019, Apple announced that a light-on dark mode will be available across all native applications in iOS 13 and iPadOS. It will also be possible for third-party developers to implement their own dark themes. Google has announced an official dark mode is coming to Android with the release of Android 10.

Materials recycling

Recycling computing equipment can keep harmful materials such as lead, mercury, and hexavalent chromium out of landfills, and can also replace equipment that otherwise would need to be manufactured, saving further energy and emissions. Computer systems that have outlived their particular function can be re-purposed, or donated to various charities and non-profit organizations. However, many charities have recently imposed minimum system requirements for donated equipment. Additionally, parts from outdated systems may be salvaged and recycled through certain retail outlets and municipal or private recycling centers. Computing supplies, such as printer cartridges, paper, and batteries may be recycled as well.

A drawback to many of these schemes is that computers gathered through recycling drives are often shipped to developing countries where environmental standards are less strict than in North America and Europe. The Silicon Valley Toxics Coalition estimates that 80% of the post-consumer e-waste collected for recycling is shipped abroad to countries such as China and Pakistan.

In 2011, the collection rate of e-waste is still very low, even in the most ecology-responsible countries like France. In this country, e-waste collection is still at a 14% annual rate between electronic equipment sold and e-waste collected for 2006 to 2009.

The recycling of old computers raises an important privacy issue. The old storage devices still hold private information, such as emails, passwords, and credit card numbers, which can be recovered simply by someone's using software available freely on the Internet. Deletion of a file does not actually remove the file from the hard drive. Before recycling a computer, users should remove the hard drive, or hard drives if there is more than one, and physically destroy it or store it somewhere safe. There are some authorized hardware recycling companies to whom the computer may be given for recycling, and they typically sign a non-disclosure agreement. 

Cloud computing

Cloud computing addresses two major ICT challenges related to Green computing – energy usage and resource consumption. Virtualization, Dynamic provisioning environment, multi-tenancy, green data center approaches are enabling cloud computing to lower carbon emissions and energy usage up to a great extent. Large enterprises and small businesses can reduce their direct energy consumption and carbon emissions by up to 30% and 90% respectively by moving certain on-premises applications into the cloud. One common example includes Online shopping that helps people purchase products and services over the Internet without requiring them to drive and waste fuel to reach out to the physical shop, which, in turn, reduces greenhouse gas emission related to travel.

Edge Computing

New technologies such as Edge and Fog computing are a solution to reducing energy consumption. These technologies allow redistributing computation near the use, thus reducing energy costs in the network. Furthermore, having smaller data centers, the energy used in operations such as refrigerating and maintenance gets largely reduced. 

Telecommuting

Teleconferencing and telepresence technologies are often implemented in green computing initiatives. The advantages are many; increased worker satisfaction, reduction of greenhouse gas emissions related to travel, and increased profit margins as a result of lower overhead costs for office space, heat, lighting, etc. The savings are significant; the average annual energy consumption for U.S. office buildings is over 23 kilowatt hours per square foot, with heat, air conditioning and lighting accounting for 70% of all energy consumed. Other related initiatives, such as Hoteling, reduce the square footage per employee as workers reserve space only when they need it. Many types of jobs, such as sales, consulting, and field service, integrate well with this technique. 

Voice over IP (VoIP) reduces the telephony wiring infrastructure by sharing the existing Ethernet copper. VoIP and phone extension mobility also made hot desking more practical. 

Telecommunication network devices energy indices

The information and communication technologies (ICTs) energy consumption, in the US and worldwide, has been estimated respectively at 9.4% and 5.3% of the total electricity produced. The energy consumption of ICTs is today significant even when compared with other industries. Some study tried to identify the key energy indices that allow a relevant comparison between different devices (network elements). This analysis was focused on how to optimise device and network consumption for carrier telecommunication by itself. The target was to allow an immediate perception of the relationship between the network technology and the environmental effect. These studies are at the start and the gap to fill in this sector is still huge and further research will be necessary. 

Supercomputers

The inaugural Green500 list was announced on November 15, 2007 at SC|07. As a complement to the TOP500, the unveiling of the Green500 ushered in a new era where supercomputers can be compared by performance-per-watt.

The TSUBAME-KFC-GSIC Center by Tokyo Institute of Technology, Made in Japan was with a great advantage to the second, the Top 1 Supercomputer in the World with 4,503.17 MFLOPS/W and 27.78 Total Power (kW)++ 

Today a new supercomputer, L-CSC from the GSI Helmholtz Center, Made in Germany emerged as the most energy-efficient (or greenest) supercomputer in the world. The L-CSC cluster was the first and only supercomputer on the list to surpass 5 gigaflops/watt (billions of operations per second per watt). L-CSC is a heterogeneous supercomputer that is powered by Dual Intel Xeon E5-260 and GPU accelerators, namely AMD FirePro™ S9150 GPUs. It marks the first time that a supercomputer using AMD GPUs has held the top spot. Each server has a memory of 256 gigabytes. Connected, the server via an Infiniband FDR network. 

Education and certification


Green computing programs

Degree and postgraduate programs that provide training in a range of information technology concentrations along with sustainable strategies in an effort to educate students how to build and maintain systems while reducing its harm to the environment. The Australian National University (ANU) offers "ICT Sustainability" as part of its information technology and engineering masters programs. Athabasca University offer a similar course "Green ICT Strategies", adapted from the ANU course notes by Tom Worthington. In the UK, Leeds Beckett University offers an MSc Sustainable Computing program in both full and part-time access modes.

Green computing certifications

Some certifications demonstrate that an individual has specific green computing knowledge, including:
  • Green Computing Initiative - GCI offers the Certified Green Computing User Specialist (CGCUS), Certified Green Computing Architect (CGCA) and Certified Green Computing Professional (CGCP) certifications.
  • CompTIA Strata Green IT is designed for IT managers to show that they have good knowledge of green IT practices and methods and why it is important to incorporate them into an organization.
  • Information Systems Examination Board (ISEB) Foundation Certificate in Green IT is appropriate for showing an overall understanding and awareness of green computing and where its implementation can be beneficial.
  • Singapore Infocomm Technology Federation (SiTF) Singapore Certified Green IT Professional is an industry endorsed professional level certification offered with SiTF authorized training partners. Certification requires completion of a four-day instructor-led core course, plus a one-day elective from an authorized vendor.
  • Australian Computer Society (ACS) The ACS offers a certificate for "Green Technology Strategies" as part of the Computer Professional Education Program (CPEP). Award of a certificate requires completion of a 12-week e-learning course designed by Tom Worthington, with written assignments.
  • International Federation of Global & Green ICT "IFGICT"- promotes Green IT Professional, Certification requires minimum 2 years in ICT industry. IFGICT is shortlisted service provider by UNFCCC - CDM.

Blogs and Web 2.0 resources

There are a lot of blogs and other user created references that can be used to gain more insights on green computing strategies, technologies and business benefits. A lot of students in Management and Engineering courses have helped in raising higher awareness about green computing.

Ratings

Since 2010, Greenpeace has maintained a list of ratings of prominent technology companies in several countries based on how clean the energy used by that company is, ranging from A (the best) to F (the worst).
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Clean technology

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Clean_technology

Clean technology is any process, product, or service that reduces negative environmental impacts through significant energy efficiency improvements, the sustainable use of resources, or environmental protection activities. Clean technology includes a broad range of technology related to recycling, renewable energy, information technology, green transportation, electric motors, green chemistry, lighting, Greywater, and more. Environmental finance is a method by which new clean technology projects that have proven that they are "additional" or "beyond business as usual" can obtain financing through the generation of carbon credits. A project that is developed with concern for climate change mitigation is also known as a carbon project.

Clean Edge, a clean technology research firm, describes clean technology "a diverse range of products, services, and processes that harness renewable materials and energy sources, dramatically reduce the use of natural resources, and cut or eliminate emissions and wastes." Clean Edge notes that, "Clean technologies are competitive with, if not superior to, their conventional counterparts. Many also offer significant additional benefits, notably their ability to improve the lives of those in both developed and developing countries".

Investments in clean technology have grown considerably since coming into the spotlight around 2000. According to the United Nations Environment Program, wind, solar, and biofuel companies received a record $148 billion in new funding in 2007 as rising oil prices and climate change policies encouraged investment in renewable energy. $50 billion of that funding went to wind power. Overall, investment in clean-energy and energy-efficiency industries rose 60 percent from 2006 to 2007. In 2009, it was forecast that the three main clean technology sectors, solar photovoltaics, wind power, and biofuels, will have revenues of $325.1 billion by 2018.

According to an MIT Energy Initiative Working Paper published in July 2016, about a half of over $25 billion funding provided by venture capital to cleantech from 2006 to 2011 was never recovered.
Clean technology has also emerged as an essential topic among businesses and companies. It can reduce pollutants and dirty fuels for every company, regardless of which industry they are in, and using clean technology has become a competitive advantage. Through building their Corporate Social Responsibility (CSR) goals, they participate in using clean technology and other means by promoting Sustainability. Fortune Global 500 firms spend around $20 billion a year on CSR activities in 2018.

Definition

Cleantech products or services are those that improve operational performance, productivity, or efficiency while reducing costs, inputs, energy consumption, waste, or environmental pollution. Its origin is the increased consumer, regulatory, and industry interest in clean forms of energy generation—specifically, perhaps, the rise in awareness of global warming, climate change, and the impact on the natural environment from the burning of fossil fuels. Cleantech is often associated with venture capital funds and land use organizations. The term has historically been differentiated from various definitions of green business, sustainability, or triple bottom line industries by its origins in the venture capital investment community and has grown to define a business sector that includes significant and high growth industries such as solar, wind, water purification, and biofuels.

Nomenclature

While the expanding industry has grown rapidly in recent years and attracted billions of dollars of capital, the clean technology space has not settled on an agreed-upon term. Cleantech, is used fairly widely, although variant spellings include ⟨clean-tech⟩ and ⟨clean tech⟩. In recent years, some clean technology companies have de-emphasized that aspect of their business to tap into broader trends, such as smart cities.

Origins of the concept

The idea of cleantech first emerged among a group of emerging technologies and industries, based on principles of biology, resource efficiency, and second-generation production concepts in basic industries. Examples include: energy efficiency, selective catalytic reduction, non-toxic materials, water purification, solar energy, wind energy, and new paradigms in energy conservation. Since the 1990s, interest in these technologies has increased with two trends: a decline in the relative cost of these technologies and a growing understanding of the link between industrial design used in the 19th century and early 20th century, such as fossil fuel power plants, the internal combustion engine, and chemical manufacturing, and an emerging understanding of human-caused impact on earth systems resulting from their use (see articles: ozone hole, acid rain, desertification, climate change and global warming).

Investment worldwide

Annual cleantech investment in North America, Europe, Israel, China, India
Year Investment ($mil)
2001
506.8
2002
883.2
2003
1,258.6
2004
1,398.3
2005
2,077.5
2006
4,520.2
2007
6,087.2
2008*
8,414.3
*2008 data preliminary
Source: Cleantech Group
In 2008, clean technology venture investments in North America, Europe, China, and India totaled a record $8.4 billion. Cleantech Venture Capital firms include NTEC, Cleantech Ventures, and Foundation Capital. The preliminary 2008 total represents the seventh consecutive year of growth in venture investing, widely recognized as a leading indicator of overall investment patterns. China is seen as a major growth market for cleantech investments currently, with a focus on renewable energy technologies. In 2014, Israel, Finland and the US were leading the Global Cleantech Innovation Index, out of 40 countries assessed, while Russia and Greece were last. With regards to private investments, the investment group Element 8 has received the 2014 CleanTech Achievement award from the CleanTech Alliance, a trade association focused on clean tech in the State of Washington, for its contribution in Washington State's cleantech industry.

According to the published research, the top clean technology sectors in 2008 were solar, biofuels, transportation, and wind. Solar accounted for almost 40% of total clean technology investment dollars in 2008, followed by biofuels at 11%.

The 2009 United Nations Climate Change Conference in Copenhagen, Denmark was expected to create a framework whereby limits would eventually be placed on greenhouse gas emissions. Many proponents of the cleantech industry hoped for an agreement to be established there to replace the Kyoto Protocol. As this treaty was expected, scholars had suggested a profound and inevitable shift from "business as usual." However, the participating States failed to provide a global framework for clean technologies. The outburst of the 2008 economic crisis then hampered private investments in clean technologies, which were back at their 2007 level only in 2014. The 2015 United Nations Climate Change Conference in Paris is expected to achieve a universal agreement on climate, which would foster clean technologies development. On 23 September 2019, the Secretary-General of the United Nations will host a Climate Action Summit in New York.

Implementation worldwide

India is one of the countries that have achieved remarkable success in sustainable development by implementing clean technology, and it became a global clean energy powerhouse. India, who was the third-largest emitter of greenhouse gases, advanced a scheme of converting to renewable energy with sun and wind from fossil fuels. This continuous effort has created an increase in the country’s renewable energy capacity (around 80 gigawatts of installed renewable energy capacity, 2019), with a compound annual growth rate of over 20%. By steadily increasing India’s renewable capacity, India is achieving the Paris Agreement with a significant reduction in producing carbon emissions. Adopting renewable energy not only brought technological advances to India, but it also impacted employment by creating around 330,000 new jobs by 2022 and more than 24 million new jobs by 2030, according to the International Labour Organization in the renewable energy sector.

Germany has been one of the renewable energy leaders in the world, and their efforts have expedited the progress after the nuclear power plant meltdown in Japan in 2011, by deciding to switch off all 17 reactors by 2022. Still, this is just one of Germany's ultimate goals; and Germany is aiming to set the usage of renewable energy at 80% by 2050, which is currently 27% (2015). Also, Germany is investing in renewable energy from offshore wind and anticipating its investment to result in one-third of total wind energy in Germany. The importance of clean technology also impacted the transportation sector of Germany, which produces 17 percent of its emission. The famous car-producing companies, Mercedes-Benz, BMW, Volkswagen, and Audi, in Germany, are also providing new electric cars to meet Germany's energy transition movement.

Africa and the Middle East has drawn worldwide attention for its potential share and new market of solar electricity. Notably, the countries in the Middle East have been utilizing their natural resources, an abundant amount of oil and gas, to develop solar electricity. Also, to practice the renewable energy, the energy ministers from 14 Arab countries signed a Memorandum of Understanding for an Arab Common Market for electricity by committing to the development of the electricity supply system with renewable energy.

United Nations: Sustainable Development Goals

United Nations: 17 Sustainable Development Goals

United Nations has set goals for the 2030 Agenda for Sustainable Development, which is called "Sustainable Development Goals" composed of 17 goals and 232 indicators total. These goals are designed to build a sustainable future and to implement in the countries (member states) in the UN. Many parts of the 17 goals are related to the usage of clean technology since it is eventually an essential part of designing a sustainable future in various areas such as land, cities, industries, climate, etc.
  • Goal 6: "Ensure availability and sustainable management of water and sanitation for all"
    • Various kinds of clean water technology are used to fulfill this goal, such as filters, technology for desalination, filtered water fountains for communities, etc.
  • Goal 7: "Ensure access to affordable, reliable, sustainable and modern energy for all"
    • Promoting countries for implementing renewable energy is making remarkable progress, such as:
      • "From 2012 to 2014, three quarters of the world’s 20 largest energy-consuming countries had reduced their energy intensity — the ratio of energy used per unit of GDP. The reduction was driven mainly by greater efficiencies in the industry and transport sectors. However, that progress is still not sufficient to meet the target of doubling the global rate of improvement in energy efficiency."
  • Goal 11: "Make cities and human settlements inclusive, safe, resilient and sustainable"
    • By designing sustainable cities and communities, clean technology takes parts in the architectural aspect, transportation, and city environment. For example:
      • Global Fuel Econom
      • y Initiative (GFEI) - Relaunched to accelerate progress on decarbonizing road transport. Its main goal for passenger vehicles, in line with SDG 7.3, is to double the energy efficiency of new vehicles by 2030. This will also help mitigate climate change by reducing harmful CO2 emissions.
  • Goal 13: "Take urgent action to combat climate change and its impacts*"
    • Greenhouse gas emissions have significantly impacted the climate, and this results in a rapid solution for consistently increasing emission levels. United Nations held the "Paris Agreement" for dealing with greenhouse gas emissions mainly within countries and for finding solutions and setting goals.
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